Variable displacement swash plate type compressor

ABSTRACT

Provided is a compressor, in which discharge capacity is changed by an actuator, exhibiting high controllability while realizing reduction in size. In the compressor, a movable body includes a rear wall, a circumferential wall, and a coupling mechanism. The coupling mechanism includes a first arm provided with a first pulling point and a second arm provided with a second pulling point. In the compressor, when the inclination angle of a swash plate is increased, the movable body pulls the swash plate via the first and second arms. At this time, in the compressor, pulling force can be applied at two points, i.e., at the first pulling point and the second pulling point. Consequently, in the compressor, even when the size of the rear wall and the circumferential wall is increased, the rigidity of the first and second arms can be made lower.

TECHNICAL FIELD

The present invention relates to a variable displacement swash plate type compressor.

BACKGROUND ART

A conventional variable displacement swash plate type compressor (hereinafter referred to as a compressor) is disclosed in Patent Literature 1. This compressor includes a housing which is formed by a front housing, a cylinder block, and a rear housing. A suction chamber and a discharge chamber are formed in each of the front housing and the rear housing. A swash plate chamber and plural cylinder bores are formed in the cylinder block. A drive shaft is rotatably supported in the housing. The swash plate chamber accommodates a swash plate, which is rotatable along with rotation of the drive shaft. A link mechanism is provided between the drive shaft and the swash plate. The link mechanism permits change of the inclination angle of the swash plate. The inclination angle is defined as an angle of the swash plate with respect to a direction perpendicular to the drive axis of the drive shaft. A piston is reciprocally accommodated in each of the cylinder bores. A pair of shoes provided for each piston serves as a conversion mechanism and reciprocates the piston in each of the cylinder bores along with rotation of the swash plate at a stroke corresponding to the inclination angle. An actuator includes a movable body and a control pressure chamber. The actuator is capable of changing the inclination angle by changing the volume of the control pressure chamber. The actuator is controlled by a control mechanism.

The swash plate has a pair of first arms extending toward the front housing and a pair of second arms extending toward the rear housing. Furthermore, a lug arm is fixed to the drive shaft. The first arms are coupled to the lug arm via a first pin. The second arms are coupled to the movable body via a second pin. The first and second arms, the lug arm, the movable body, and the first and second pins constitute the link mechanism.

In this compressor, the control mechanism raises the pressure in the control pressure chamber by using the pressure of refrigerant in the discharge chamber and thereby increases the inclination angle of the swash plate via the link mechanism. At this time, the movable body pushes the swash plate via the second arms. The swash plate pushed by the movable body pushes the lug arm via the first arms. As a result, the length of the link mechanism in an axial direction of the drive shaft is reduced, and thereby, the inclination angle of the swash plate is increased. In this way, discharge capacity per rotation of the drive shaft is increased in this compressor.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Laid-Open No. 5-172052

SUMMARY OF INVENTION Technical Problem

In a compressor in which the discharge capacity is changed by an actuator as described above, higher controllability may be required.

To deal with this, in the conventional compressor described above, it is conceivable to upsize the movable body in a radial direction in order to reliably increase the discharge capacity using the pressure rise in the control pressure chamber. In this case, however, in order to prevent interference between the movable body and the swash plate when its inclination angle is large, the swash plate chamber has to be upsized, and therefore the compressor has to be upsized.

Furthermore, in this compressor, since the inclination angle is increased by having the movable body push the swash plate, the movable body needs to push the swash plate with a large pushing force against a compressive reaction force and a suction reaction force which gradually increase. Consequently, in the compressor, when the inclination angle is increased, a large pushing force acts on the second arms. If it is attempted to provide the second arms with high rigidity enough to withstand the load of such a pushing force, the size of the second arms will need to be increased. The same applies to the first arms. If the size of the movable body is increased in the radial direction as described above, the first and second arms will need to have higher rigidity because the pushing force acting on the first and second arms will become greater. Such upsizing of the first and second arms will also lead to the upsizing of the swash plate chamber.

The present invention has been made in view of the conventional circumstances described above, and an object of the invention is to provide a compressor, in which discharge capacity is changed by an actuator, exhibiting high controllability while realizing reduction in size.

Solution to Problem

A variable displacement swash plate type compressor according to the present invention comprises: a housing in which a suction chamber, a discharge chamber, a swash plate chamber, and at least one cylinder bore are formed; a drive shaft extending along a drive axis and rotatably supported in the housing; a swash plate rotatable in the swash plate chamber along with rotation of the drive shaft; a link mechanism that is provided between the drive shaft and the swash plate and permits change of an inclination angle of the swash plate in a direction perpendicular to the drive axis of the drive shaft; a piston reciprocally accommodated in the cylinder bore; a conversion mechanism that reciprocates the piston in the cylinder bore along with rotation of the swash plate at a stroke corresponding to the inclination angle; an actuator that is disposed in the swash plate chamber and capable of changing the inclination angle; and a control mechanism that controls the actuator,

wherein the suction chamber and the swash plate chamber communicate with each other,

the actuator includes a partition body provided on the drive shaft, a movable body that is coupled to the swash plate via a coupling mechanism and movable with respect to the partition body along the drive axis of the drive shaft, and a control pressure chamber that is defined by the partition body and the movable body and moves the movable body by introducing a refrigerant from the discharge chamber,

the movable body is disposed so as to increase the inclination angle by pulling the swash plate when pressure in the control pressure chamber increases,

the link mechanism includes a coupling portion that is coupled to the swash plate, and

the coupling mechanism is disposed on an opposite side of the coupling portion with respect to the drive shaft and includes a first arm and a second arm provided at the movable body across the drive axis.

In the compressor according to the present invention, when the inclination angle of the swash plate is increased, the movable body pulls the swash plate. In other words, in this compressor, when the swash plate is displaced in a direction of increasing the inclination angle, the movable body moves away from the swash plate. Consequently, in the compressor, even if the size of the movable body is increased in order to reliably increase the discharge capacity due to the pressure rise in the control pressure chamber, the movable body does not interfere with the swash plate. Therefore, it is possible in this compressor to prevent upsizing of the swash plate chamber.

In this compressor, the movable body is coupled to the swash plate via the coupling mechanism. The movable body applies a pulling force to the swash plate via the coupling mechanism in order to increase the inclination angle of the swash plate. In the case where the inclination angle is increased by pulling the swash plate, less compressive reaction force and less suction reaction force are exerted as compared with the case where the inclination angle is increased by pushing the swash plate. Therefore, in this compressor, a large pulling force is not required to increase the inclination angle of the swash plate.

Furthermore, in this compressor, the coupling mechanism includes the first arm and the second arm. The first arm and the second arm are provided on the movable body across the drive axis. The pulling force can be applied by the first arm and the second arm. Therefore, in this compressor, the pulling force that each of the first arm and the second arm exerts on the swash plate can be made less as compared with the case where, for example, the coupling mechanism has only a single arm. In the compressor, although the movable body pushes the swash plate via the first and second arms when the inclination angle of the swash plate is decreased, the pushing force at that time is not so large. This is because a centrifugal force acts on a rotating body, which includes the swash plate and the movable body, in a direction of decreasing the inclination angle.

For these reasons, as described above, even when the size of the movable body is increased in this compressor, the rigidity of the first arm and the second arm required thereby can be made lower. Therefore, it is possible in this compressor to prevent upsizing of the coupling mechanism.

Thus, the compressor according to the present invention, in which the discharge capacity is changed by an actuator, exhibits high controllability while realizing reduction in size.

In the compressor according to the present invention, the at least one cylinder bore comprises at least a first cylinder bore, a second cylinder bore, and a third cylinder bore. The first cylinder bore, the second cylinder bore, and the third cylinder bore may be arranged concentrically at equal angular intervals around the drive axis in the housing. A first imaginary region and a second imaginary region may be set in the swash plate chamber. The first imaginary region is defined by a first tangential line drawn from the drive axis to the first cylinder bore at a side of the second cylinder bore and a second tangential line drawn from the drive axis to the second cylinder bore at a side of the first cylinder bore. The second imaginary region is defined by a third tangential line drawn from the drive axis to the second cylinder bore at a side of the third cylinder bore and a fourth tangential line drawn from the drive axis to the third cylinder bore at a side of the second cylinder bore. It is preferable that the first arm is located within the first imaginary region and the second arm is located within the second imaginary region.

In this case, the first arm and the second arm do not obstruct the pistons reciprocating in the first to third cylinder bores. Therefore, it is possible to surely reduce the size of the compressor.

The swash plate may be provided with a pulled portion that protrudes between the first arm and the second arm. It is preferable that a driving force is transmitted between the first arm, the second arm, and the pulled portion. In this case, the movable body stably rotates together with the drive shaft, and the swash plate also stably rotates together with the movable body and thus together with the drive shaft.

In the compressor according to the present invention, the first arm and the second arm may be separately coupled to the pulled portion by using different pins or the like.

In particular, it is preferable that a pin extending in a direction perpendicular to the drive axis is inserted through the first arm, the pulled portion, and the second arm. In this case, the first arm, the pulled portion, and the second arm can be coupled together easily. In this case, it is further possible to reduce the number of components and facilitate manufacturing as compared with the case of using different pins to couple the first arm and the pulled portion and couple the second arm and the pulled portion respectively as described above. Furthermore, in this case, the pin is less likely to come off the first arm, the second arm, and the pulled portion, and thus reliability is improved.

Advantageous Effects of Invention

The compressor according to the present invention, in which the discharge capacity can be changed by the actuator, exhibits high controllability while realizing reduction in size.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view of a compressor according to an embodiment at the time of maximum displacement.

FIG. 2 is a schematic diagram showing a control mechanism of the compressor according to the embodiment.

FIG. 3 is a sectional view of the compressor according to the embodiment when taken along the line and viewed in the direction of arrow III in FIG. 1.

FIG. 4A is a front view showing a swash plate of the compressor according to the embodiment.

FIG. 4B is a sectional view showing the swash plate of the compressor according to the embodiment.

FIG. 5 is a sectional view of the compressor according to the embodiment at the time of minimum displacement.

FIG. 6 is a perspective view showing a movable body of the compressor according to the embodiment when viewed from the front.

FIG. 7 is a schematic top view showing the movable body of the compressor according to the embodiment.

DESCRIPTION OF EMBODIMENTS

An embodiment, which embodies the present invention, will be described below with reference to the drawings. The compressor according to the embodiment is a variable displacement double head swash plate type compressor. This compressor is mounted on a vehicle and constitutes a refrigeration circuit of vehicle air-conditioning apparatus.

As shown in FIG. 1, a compressor according to the embodiment comprises a housing 1, a drive shaft 3, a swash plate 5, a link mechanism 7, plural pistons 9, a pair of shoes 11 a and 11 b, and an actuator 13 as well as a control mechanism 15 which is shown in FIG. 2.

As shown in FIG. 1, the housing 1 includes a rear housing 17 located at a rear position in the compressor, a front housing 19 located at a front position in the compressor, first and second cylinder blocks 21 and 23 located between the front housing 19 and the rear housing 17, and first and second valve forming plates 39 and 41.

The aforementioned control mechanism 15 is provided in the rear housing 17. Also, a first suction chamber 27 a, a first discharge chamber 29 a, and a pressure regulation chamber 31 are formed in the rear housing 17. The pressure regulation chamber 31 is located in central part of the rear housing 17. The first suction chamber 27 a is formed into an annular shape and located on an outer peripheral side of the pressure regulation chamber 31 in the rear housing 17. The first discharge chamber 29 a is also formed into an annular shape and located on an outer peripheral side of the first suction chamber 27 a in the rear housing 17.

A first rear-side communication passage 18 a is formed in the rear housing 17. The rear end of the first rear-side communication passage 18 a communicates with the first discharge chamber 29 a, and the front end thereof opens at the front end of the rear housing 17.

A boss 19 a, which protrudes frontward, is formed in the front housing 19. A shaft seal device 25 is provided in the boss 19 a. A second suction chamber 27 b and a second discharge chamber 29 b are formed in the front housing 19. The second suction chamber 27 b is located on an inner peripheral side in the front housing 19. The second discharge chamber 29 b is formed into an annular shape and located on an outer peripheral side of the second suction chamber 27 b in the front housing 19.

A first front-side communication passage 20 a is formed in the front housing 19. The front end of the first front-side communication passage 20 a communicates with the second discharge chamber 29 b, and the rear end thereof opens at the rear end of the front housing 19.

A swash plate chamber 33 is formed between the first cylinder block 21 and the second cylinder block 23. The swash plate chamber 33 is located at an approximate center in the front-rear direction of the housing 1.

As shown in FIG. 3, first to fifth rear-side cylinder bores 21 a to 21 e are formed in the first cylinder block 21 so as to be parallel to one another at equal angular intervals in a circumferential direction. Also, as shown in FIG. 1, a first shaft hole 211 is formed in the first cylinder block 21 to allow the drive shaft 3 to be inserted therethrough. The rear end of the first shaft hole 211 communicates with the pressure regulation chamber 31. A first sliding bearing 22 a is provided in the first shaft hole 211. A roller bearing may be provided instead of the first sliding bearing 22 a.

The first cylinder block 21 has a first recess 212, which communicates with the first shaft hole 211 and is coaxial with the first shaft hole 211. The first recess 212 also communicates with the swash plate chamber 33 and forms part of the swash plate chamber 33. The first recess 212 is shaped such that its diameter becomes smaller toward the rear end in a stepwise manner. A first thrust bearing 35 a is provided on the rear end of the first recess 212. As shown in FIG. 3, five connecting passages 37 a are formed in the first cylinder block 21 to allow the swash plate chamber 33 to communicate with the first suction chamber 27 a. The connecting passages 37 a are formed at equal angular intervals in the circumferential direction so as to be located between the respective first to fifth rear-side cylinder bores 21 a to 21 e. Also, as shown in FIG. 1, a first retainer groove 213 is provided in the first cylinder block 21 to restrict a maximum opening degree of first suction reed valves 391 a described later.

The first cylinder block 21 includes an outlet port 160, a confluence discharge chamber 161, a third front-side communication passage 20 c, a second rear-side communication passage 18 b, and an inlet port 330. The front end of the second rear-side communication passage 18 b communicates with the confluence discharge chamber 161 and the rear end thereof opens at the rear end of the first cylinder block 21. The outlet port 160 and the confluence discharge chamber 161 communicate with each other. Via the outlet port 160, the confluence discharge chamber 161 is connected to a condenser (not shown) constituting a refrigeration circuit. The front end of the third front-side communication passage 20 c opens at the front end of the first cylinder block 21, and the rear end thereof communicates with the confluence discharge chamber 161. The inlet port 330 communicates with the swash plate chamber 33. This inlet port 330 is connected to an evaporator (not shown) constituting the refrigeration circuit.

The second cylinder block 23 has a first front-side cylinder bore 23 a which corresponds to the first rear-side cylinder bore 21 a. Thereby, the first rear-side cylinder bore 21 a is paired with the first front-side cylinder bore 23 a in the front-rear direction. The first rear-side cylinder bore 21 a and the first front-side cylinder bore 23 a are equal in diameter. Similarly, the second cylinder block 23 has second to fifth front-side cylinder bores (not shown) which correspond respectively to the second to fifth rear-side cylinder bores 21 b to 21 e.

A second shaft hole 23 b is formed in the second cylinder block 23 to allow the drive shaft 3 to be inserted therethrough. A second sliding bearing 22 b is provided in the second shaft hole 23 b. A roller bearing may be provided instead of the second sliding bearing 22 b.

The second cylinder block 23 has a second recess 23 c, which communicates with the second shaft hole 23 b and is coaxial with the second shaft hole 23 b. The second recess 23 c also communicates with the swash plate chamber 33 and forms part of the swash plate chamber 33. Thereby, the rear end of the second shaft hole 23 b communicates with the swash plate chamber 33. The second recess 23 c is shaped such that its diameter becomes smaller toward the front end in a stepwise manner. A second thrust bearing 35 b is provided on the front end of the second recess 23 c. Plural connecting passages 37 b are formed in the second cylinder block 23 to allow the swash plate chamber 33 to communicate with the second suction chamber 27 b. Also, a second retainer groove 23 e is provided in the second cylinder block 23 to restrict a maximum opening degree of respective suction reed valves 411 a described later.

A second front-side communication passage 20 b is formed in the second cylinder block 23. The front end of the second front-side communication passage 20 b opens at the front end of the second cylinder block 23, and the rear end thereof opens at the rear end the second cylinder block 23. The second front-side communication passage 20 b communicates with the front end of the third front-side communication passage 20 c when the first cylinder block 21 and the second cylinder block 23 are joined together.

The first valve forming plate 39 is provided between the rear housing 17 and the first cylinder block 21. Also, the second valve forming plate 41 is provided between the front housing 19 and the second cylinder block 23.

The first valve forming plate 39 includes a first valve plate 390, a first suction valve plate 391, a first discharge valve plate 392, and a first retainer plate 393. Plural first suction ports 390 a, which correspond respectively to the first to fifth rear-side cylinder bores 21 a to 21 e, are formed in the first valve plate 390, the first discharge valve plate 392, and the first retainer plate 393. Plural first discharge ports 390 b, which correspond respectively to the first to fifth rear-side cylinder bores 21 a to 21 e, are formed in the first valve plate 390 and the first suction valve plate 391. A first suction communication hole 390 c is formed in the first valve plate 390, the first suction valve plate 391, the first discharge valve plate 392, and the first retainer plate 393. A first discharge communication hole 390 d is formed in the first valve plate 390 and the first suction valve plate 391.

The first to fifth rear-side cylinder bores 21 a to 21 e communicate with the first suction chamber 27 a through the respective first suction ports 390 a. Also, the first to fifth rear-side cylinder bores 21 a to 21 e communicate with the first discharge chamber 29 a through the respective first discharge ports 390 b. The first suction chamber 27 a communicates with the connecting passages 37 a through the first suction communication hole 390 c. The first rear-side communication passage 18 a communicates with the second rear-side communication passage 18 b through the first discharge communication hole 390 d.

The first suction valve plate 391 is provided on the front face of the first valve plate 390. The first suction valve plate 391 has the first suction reed valves 391 a, the number of which is equal to the number of the first suction ports 390 a, capable of opening and closing the respective first suction ports 390 a by elastic deformation. The first discharge valve plate 392 is provided on the rear face of the first valve plate 390. The first discharge valve plate 392 has first discharge reed valves 392 a, the number of which is equal to the number of the first discharge ports 390 b, capable of opening and closing the respective first discharge ports 390 b by elastic deformation. The first retainer plate 393 is provided on the rear face of the first discharge valve plate 392. The first retainer plate 393 restricts a maximum opening degree of the respective first discharge reed valves 392 a.

The second valve forming plate 41 includes a second valve plate 410, a second suction valve plate 411, a second discharge valve plate 412, and a second retainer plate 413. Second suction ports 410 a, the number of which is equal to the number of the first to fifth front-side cylinder bores 23 a, are formed in the second valve plate 410, the second discharge valve plate 412, and the second retainer plate 413. Second discharge ports 410 b, the number of which is equal to the number of the first to fifth front-side cylinder bores 23 a, are formed in the second valve plate 410 and the second suction valve plate 411. A second suction communication hole 410 c is formed in the second valve plate 410, the second suction valve plate 411, the second discharge valve plate 412, and the second retainer plate 413. A second discharge communication hole 410 d is formed in the second valve plate 410 and the second suction valve plate 411.

The first to fifth front-side cylinder bores 23 a communicate with the second suction chamber 27 b through the respective second suction ports 410 a. Also, the first to fifth front-side cylinder bores 23 a communicate with the second discharge chamber 29 b through the respective second discharge ports 410 b. The second suction chamber 27 b communicates with the connecting passages 37 b through the second suction communication hole 410 c. The first front-side communication passage 20 a communicates with the second front-side communication passage 20 b through the second discharge communication hole 410 d.

The second suction valve plate 411 is provided on the rear face of the second valve plate 410. The second suction valve plate 411 has the second suction reed valves 411 a, the number of which is equal to the number of the second suction ports 410 a, capable of opening and closing the respective second suction ports 410 a by elastic deformation. Also, the second discharge valve plate 412 is provided on the front face of the second valve plate 410. The second discharge valve plate 412 has second discharge reed valves 412 a, the number of which is equal to the number of the second discharge ports 410 b, capable of opening and closing the respective second discharge ports 410 b by elastic deformation. The second retainer plate 413 is provided on the front face of the second discharge valve plate 412. The second retainer plate 413 restricts a maximum opening degree of the respective second discharge reed valves 412 a.

In the compressor, a first discharge communication passage 18 is formed by the first rear-side communication passage 18 a, the first discharge communication hole 390 d, and the second rear-side communication passage 18 b. Also, a second discharge communication passage 20 is formed by the first front-side communication passage 20 a, the second discharge communication hole 410 d, the second front-side communication passage 20 b, and the third front-side communication passage 20 c.

Also, in the compressor, the first and second suction chambers 27 a and 27 b and the swash plate chamber 33 communicate with each other via the connecting passages 37 a and 37 b and the first and second suction communication holes 390 c and 410 c. Accordingly, the pressure in the first and second suction chambers 27 a and 27 b and the swash plate chamber 33 are substantially equal. Because a low-pressure refrigerant gas which has passed through an evaporator flows into the swash plate chamber 33 through the inlet port 330, the pressure in the swash plate chamber 33 and the first and second suction chambers 27 a and 27 b is lower than the pressure in the first and second discharge chambers 29 a and 29 b.

The drive shaft 3 is made up of a drive shaft body 30 extending along a drive axis O, a first support member 43 a, and a second support member 43 b. A first small-diameter portion 30 a is formed on the rear end side of the drive shaft body 30, and a second small-diameter portion 30 b is formed on the front end side of the drive shaft body 30. The drive shaft body 30 extends rearward from the front side of the housing 1 by being inserted rearward from the boss 19 a through the first and second sliding bearings 22 a and 22 b. Consequently, the drive shaft body 30 and thus the drive shaft 3 are supported by the housing 1 so as to be rotatable around the drive axis O. The front end of the drive shaft body 30 is located in the boss 19 a and the rear end thereof protrudes into the pressure regulation chamber 31.

The swash plate 5, the link mechanism 7, and the actuator 13 are provided on the drive shaft body 30. The swash plate 5, the link mechanism 7, and the actuator 13 are all disposed in the swash plate chamber 33.

The first support member 43 a is press-fitted to the rear end of the first small-diameter portion 30 a of the drive shaft body 30 and located in the first shaft hole 211. A flange 430 is formed on the front end of the first support member 43 a. The flange 430 protrudes into the first recess 212 and abuts the first thrust bearing 35 a. The rear end of the first support member 43 a protrudes into the pressure regulation chamber 31. In the first support member 43 a, a first slide member 431 and a second slide member 432 made of resin are provided in the rear of the flange 430. The first and second slide members 431 and 432 are in contact with and slidable along an inner circumferential surface of the first shaft hole 211.

The second support member 43 b is press-fitted to the second small-diameter portion 30 b of the drive shaft body 30 and located inside of the second sliding bearing 22 b in the second shaft hole 23 b. Also, the second support member 43 b includes a flange 433 configured to abut the second thrust bearing 35 b and a mounting portion (not shown) configured to allow a second pin 47 b, which will be described later, to be inserted therethrough. A front end of a first return spring 44 a is fixed to the second support member 43 b. The first return spring 44 a extends from the second support member 43 b toward the swash plate chamber 33 along the drive axis O.

The swash plate 5 has a flat annular shape and includes a front face 5 a and a rear face 5 b. The front face 5 a faces frontward of the compressor in the swash plate chamber 33. Also, the rear face 5 b faces rearward of the compressor in the swash plate chamber 33.

The swash plate 5 includes a ring plate 45. As shown in FIG. 4, the ring plate 45 has a flat annular shape with an insertion hole 45 a formed in the center. The swash plate 5 is attached to the drive shaft 3 by inserting the drive shaft body 30 through the insertion hole 45 a in the swash plate chamber 33 (see FIG. 1).

Also, as shown in FIG. 4A, a groove 45 b is formed on one end side of the ring plate 45 and a pulled portion 45 c is formed on the opposite end side of the ring plate 45. As shown in FIG. 4B, the groove 45 b extends through the swash plate 5 from the front face 5 a to the rear face 5 b. The pulled portion 45 c protrudes from the rear face 5 b toward the rear of the swash plate 5 so as to be located between first and second arms 132 and 133 described later. A pin hole 450 is formed in the pulled portion 45 c.

As shown in FIG. 1, the link mechanism 7 has a lug arm 49. The lug arm 49 is placed frontward relative to the swash plate 5 in the swash plate chamber 33 and located between the swash plate 5 and the second support member 43 b. The lug arm 49 is formed so as to be substantially L-shaped from the front end toward the rear end. A weight 49 a is formed at the rear end of the lug arm 49. The weight 49 a extends approximately half around a circumference of the actuator 13. The shape of the weight 49 a may be designed as appropriate.

The rear end side of the lug arm 49 is connected to the one end side of the ring plate 45 with a first pin 47 a. The first pin 47 a corresponds to the coupling portion according to the present invention. When the axis of the first pin 47 a is defined as a first pivot axis M1, the rear end side of the lug arm 49 is supported around the first pivot axis M1 so as to be pivotable with respect to the one end side of the ring plate 45, i.e., the swash plate 5. The first pivot axis M1 extends in a direction perpendicular to the drive axis O of the drive shaft 3.

The front end of the lug arm 49 is connected to the second support member 43 b via the second pin 47 b. When the axis of the second pin 47 b is defined as a second pivot axis M2, the front end of the lug arm 49 is supported around the second pivot axis M2 so as to be pivotable with respect to the second support member 43 b, i.e., the drive shaft 3. The second pivot axis M2 extends parallel to the first pivot axis M1. The link mechanism 7 according to the present invention is made up of the lug arm 49, the first and second pins 47 a and 47 b, and in addition, the first and second arms 132 and 133 and a third pin 47 c, which will be described later.

The weight 49 a is provided so as to extend at the rear end of the lug arm 49, i.e., extend on the opposite side of the second pivot axis M2 with reference to the first pivot axis M1. As the lug arm 49 is supported by the ring plate 45 with the first pin 47 a, the weight 49 a passes through the groove 45 b in the ring plate 45 and reaches the rear face side of the ring plate 45, i.e., the side of the rear face 5 b of the swash plate 5. Therefore, a centrifugal force produced by rotation of the swash plate 5 around the drive axis O also acts on the weight 49 a at the side of the rear face 5 b of the swash plate 5.

In this compressor, the swash plate 5 is able to rotate together with the drive shaft 3 as the swash plate 5 is connected to the drive shaft 3 by the link mechanism 7. Also, the swash plate 5 is able to change its inclination angle due to the pivotal movement of both ends of the lug arm 49 around the first pivot axis M1 and the second pivot axis M2, respectively.

The pistons 9 each has a first head 9 a at its rear end and a second head 9 b at its front end. The first head 9 a is reciprocally accommodated in each of the first to fifth rear-side cylinder bores 21 a to 21 e. The first head 9 a and the first valve forming plate 39 define a first compression chamber 210 in each of the first to fifth rear-side cylinder bores 21 a to 21 e. The second head 9 b is reciprocally accommodated in each of the first to fifth front-side cylinder bores 23 a. The second head 9 b and the second valve forming plate 41 define a second compression chamber 230 in each of the first to fifth front-side cylinder bores 23 a.

An engaging portion 9 c is formed in the middle of each of the pistons 9. Hemispherical shoes 11 a and 11 b are provided in each of the engaging portions 9 c. The shoes 11 a and 11 b convert rotation of the swash plate 5 into reciprocating movement of the pistons 9. The shoes 11 a and 11 b correspond to the conversion mechanism according to the present invention. Thus, the respective first heads 9 a are able to reciprocate in the first to fifth rear-side cylinder bores 21 a to 21 e and the respective second heads 9 b are able to reciprocate in the first to fifth front-side cylinder bores 23 a at a stroke corresponding to the inclination angle of the swash plate 5.

Here, in the compressor, when the stroke of the pistons 9 changes according to the change in the inclination angle of the swash plate 5, respective top dead center positions of the first heads 9 a and the second heads 9 b move. Specifically, as shown in FIG. 5, as the inclination angle of the swash plate 5 decreases, the top dead center positions of the first and second heads 9 a and 9 b move such that the volume of the first compression chamber 210 become larger than the volume of the second compression chamber 230.

The actuator 13 is placed in the swash plate chamber 33. The actuator 13 is located rearward of the swash plate 5 in the swash plate chamber 33 and able to advance into the first recess 212. The actuator 13 includes a movable body 13 a, a partition body 13 b, and a control pressure chamber 13 c. The control pressure chamber 13 c is formed between the movable body 13 a and the partition body 13 b.

As shown in FIG. 6, the movable body 13 a includes a rear wall 130, a circumferential wall 131, and a coupling mechanism 14. The rear wall 130 is located at a rear position in the movable body 13 a and extends radially in a direction away from the drive axis O. The rear wall 130 has an insertion hole 130 a through which the first small-diameter portion 30 a of the drive shaft body 30 is inserted. The circumferential wall 131 continues from an outer circumferential edge of the rear wall 130 and extends frontward at the movable body 13 a. The movable body 13 a is formed into a bottomed cylindrical shape by the rear wall 130, the circumferential wall 131, and the coupling mechanism 14.

The coupling mechanism 14 has the first arm 132 and the second arm 133. The first arm 132 and the second arm 133 are formed at the front end of the circumferential wall 131 and protrude frontward of the movable body 13 a. Specifically, the first arm 132 is formed at the left front end of the circumferential wall 131, while the second arm 133 is formed at the right front end of the circumferential wall 131. Since the first arm 132 and the second arm 133 protrude frontward of the movable body 13 a in this way, a recessed portion 134 is formed between the first arm 132 and the second arm 133 by the first and second arms 132 and 133 and the front end face of the circumferential wall 131. A first pulling point 132 a is set on the first arm 132 and a second pulling point 133 a is set on the second arm 133. The first and second pulling points 132 a and 133 a also serve as pin holes through which the third pin 47 c is inserted.

As shown in FIG. 7, the first arm 132 and the second arm 133 are formed symmetrically and disposed across the drive axis O. More specifically, the first arm 132 and the second arm 133 face each other across an imaginary plane X which is defined by the drive axis O, the top dead center position of the swash plate 5, and the bottom dead center position of the swash plate 5. Accordingly, the first pulling point 132 a and the second pulling point 133 a of the movable body 13 a are also disposed across the imaginary plane X. For ease of explanation, the shape of the first and second arms 132 and 133 etc. is simplified in FIG. 7.

As shown in FIG. 1, the partition body 13 b is formed in a disk shape having a diameter that is substantially equal to the inside diameter of the movable body 13 a. A second return spring 44 b is provided between the partition body 13 b and ring plate 45. Specifically, the rear end of the second return spring 44 b is fixed to the partition body 13 b and the front end of the second return spring 44 b is fixed to the opposite end side of the ring plate 45.

The first small-diameter portion 30 a of the drive shaft body 30 is inserted through the movable body 13 a and the partition body 13 b. The movable body 13 a is attached to the drive shaft body 30 so as to be accommodated in the first recess 212 and faces the link mechanism 7 across the swash plate 5. The partition body 13 b is placed in the movable body 13 a at a position rearward of the swash plate 5, and its periphery is surrounded by the circumferential wall 131. Consequently, the control pressure chamber 13 c is formed between the movable body 13 a and the partition body 13 b. The control pressure chamber 13 c is partitioned from the swash plate chamber 33 by the rear wall 130 and the circumferential wall 131 of the movable body 13 a and the partition body 13 b.

In the compressor, due to the insertion of the first small-diameter portion 30 a, the movable body 13 a is able to rotate with the drive shaft 3 and move along the drive axis O of the drive shaft 3 in the swash plate chamber 33. On the other hand, the partition body 13 b is fixed to the first small-diameter portion 30 a in the state that the first small-diameter portion 30 a has been inserted therethrough. The partition body 13 b is thus only able to rotate together with the drive shaft 3, and not able to move in the same manner as the movable body 13 a. As a result, the movable body 13 a moves along the drive axis O relative to the partition body 13 b. The partition body 13 b may be provided on the drive shaft body 30 so as to be movable along the drive axis O.

As shown in FIG. 3, a first imaginary region S1 and a second imaginary region S2 are set in the swash plate chamber 33. The first imaginary region S1 is defined by a first tangential line L1 drawn from the drive axis O to the first rear-side cylinder bore 21 a at a side of the second rear-side cylinder bore 21 b and a second tangential line L2 drawn from the drive axis O to the second rear-side cylinder bore 21 b at a side of the first rear-side cylinder bore 21 a. The second imaginary region S2 is defined by a third tangential line L3 drawn from the drive axis O to the second rear-side cylinder bore 21 b at a side of the third rear-side cylinder bore 21 c and a fourth tangential line L4 drawn from the drive axis O to the third rear-side cylinder bore 21 c at a side of the second rear-side cylinder bore 21 b.

In the compressor, the first and second arms 132 and 133 are formed such that when the movable body 13 a is attached to the drive shaft body 30, the first arm 132 is positioned in the first imaginary region S1 and the second arm 133 is positioned in the second imaginary region S2. For ease of explanation, the shape of the first and second arms 132 and 133 is simplified in FIG. 3.

As shown in FIG. 1, the first and second arms 132 and 133 are connected with the swash plate 5 with the third pin 47 c. Specifically, the pulled portion 45 c shown in FIG. 4 is fitted to the recessed portion 134 of the movable body 13 a, and in this state, the first and second arms 132 and 133 are connected with the pulled portion 45 c by the third pin 47 c alone. Consequently, the coupling mechanism 14 is placed on the opposite side of the first pin 47 a across the drive shaft 3, i.e., the drive axis O.

The third pin 47 c extends in a direction perpendicular to the drive axis O from the first pulling point 132 a to the second pulling point 133 a through the pin hole 450 of the pulled portion 45 c. Thereby, as shown in FIG. 1, when the axis of the third pin 47 c is defined as an action axis M3, the swash plate 5 is supported by the movable body 13 a so as to be pivotable around the action axis M3. The action axis M3 extends parallel to the first and second pivot axes M1 and M2. The movable body 13 a is coupled to the swash plate 5 in this way.

The first small-diameter portion 30 a has an axial path 3 a, which extends frontward from the rear end along the drive axis O, and a radial path 3 b, which extends in a radial direction from the front end of the axial path 3 a and opens at an outer circumferential surface of the drive shaft body 30. The rear end of the axial path 3 a opens to the pressure regulation chamber 31. The radial path 3 b opens to the control pressure chamber 13 c. The control pressure chamber 13 c thus communicates with the pressure regulation chamber 31 through the radial path 3 b and the axial path 3 a.

A threaded portion 3 d is formed on a tip end of the drive shaft body 30. Via the threaded portion 3 d, the drive shaft 3 is connected to a pulley or an electro-magnetic clutch (not shown).

As shown in FIG. 2, the control mechanism 15 includes a low-pressure passage 15 a, a high-pressure passage 15 b, a control valve 15 c, an orifice 15 d, the axial path 3 a, and the radial path 3 b.

The low-pressure passage 15 a is connected to the pressure regulation chamber 31 and the first suction chamber 27 a. The control pressure chamber 13 c, the pressure regulation chamber 31, and the first suction chamber 27 a communicate with one another through the low-pressure passage 15 a, the axial path 3 a, and the radial path 3 b. The high-pressure passage 15 b is connected to the pressure regulation chamber 31 and the first discharge chamber 29 a. The control pressure chamber 13 c, the pressure regulation chamber 31, and the first discharge chamber 29 a communicate with one another through the high-pressure passage 15 b, the axial path 3 a, and the radial path 3 b. The orifice 15 d is provided in the high-pressure passage 15 b.

The control valve 15 c is provided on the low-pressure passage 15 a. The control valve 15 c is able to adjust an opening degree of the low-pressure passage 15 a based on the pressure in the first suction chamber 27 a.

In the compressor, the inlet port 330 shown in FIG. 1 is connected with a pipe leading to the evaporator while the outlet port 160 is connected with a pipe leading to the condenser. The condenser is connected to the evaporator through a pipe and an expansion valve. The compressor, the evaporator, the expansion valve, the condenser, etc. constitute the refrigeration circuit of vehicle air-conditioning apparatus. Illustration of the evaporator, the expansion valve, the condenser, and the pipes is omitted.

In the compressor configured as described above, by rotation of the drive shaft 3, the swash plate 5 rotates and the pistons 9 reciprocate in the first to fifth rear-side cylinder bores 21 a to 21 e and the first to fifth front-side cylinder bores 23 a. Thereby, the first and second compression chambers 210 and 230 change their volumes according to the piston stroke. In the compressor, a suction phase for sucking refrigerant gas into the first and second compression chambers 210 and 230, a compression phase for compressing the refrigerant gas in the first and second compression chambers 210 and 230, and a discharge phase for discharging the compressed refrigerant gas into the first and second discharge chambers 29 a and 29 b take place repeatedly.

The refrigerant gas discharged into the first discharge chamber 29 a passes through the first discharge communication passage 18 and reaches the confluence discharge chamber 161. Similarly, the refrigerant gas discharged into the second discharge chamber 29 b passes through the second discharge communication passage 20 and reaches the confluence discharge chamber 161. After reaching the confluence discharge chamber 161, the refrigerant gas is discharged to the condenser through the outlet port 160.

While the suction stroke and so forth take place, a piston compression force to reduce the inclination angle of the swash plate 5 is applied to a rotation body made up of the swash plate 5, the ring plate 45, the lug arm 49, and the first pin 47 a. When the inclination angle of the swash plate 5 is changed, the stroke of the pistons 9 increases or decreases, and thereby it is possible to control the displacement.

Specifically, when the control valve 15 c, which is shown in FIG. 2, of the control mechanism 15 increases the opening degree of the low-pressure passage 15 a, the pressure in the pressure regulation chamber 31, and thus the pressure in the control pressure chamber 13 c becomes substantially equal to the pressure in the first suction chamber 27 a. Therefore, due to the piston compression force acting on the swash plate 5, the movable body 13 a of the actuator 13 moves frontward in the swash plate chamber 33 as shown in FIG. 5.

Consequently, in the compressor, the movable body 13 a pushes the swash plate 5 at the opposite end side frontward in the swash plate chamber 33 about the action axis M3 via the first and second pulling points 132 a and 133 a of the first and second arms 132 and 133. Thus, in the compressor, the opposite end side of the ring plate 45, i.e., the opposite end side of the swash plate 5, pivots clockwise around the action axis M3 against a biasing force of the second return spring 44 b. Also, the rear side of the lug arm 49 pivots counterclockwise around the first pivot axis M1 and the front end of the lug arm 49 pivots counterclockwise around the second pivot axis M2. The lug arm 49 thus comes close to the flange 433 of the second support member 43 b. In this way, the swash plate 5 pivots using the action axis M3 as a point of action and using the first pivot axis M1 as a fulcrum. This reduces the inclination angle of the swash plate 5 with respect to a direction perpendicular to the drive axis O of the drive shaft 3 and decreases the stroke of the piston 9. Therefore, the discharge capacity of the compressor per rotation of the drive shaft 3 decreases. The inclination angle of the swash plate 5 shown in FIG. 5 is the minimum value in this compressor.

Here, in this compressor, the centrifugal force acting on the weight 49 a is also applied to the swash plate 5. Thus, the swash plate 5 of this compressor is easily displaced in a direction of decreasing the inclination angle.

When the inclination angle of the swash plate 5 decreases, the ring plate 45 abuts the rear end of the first return spring 44 a. The first return spring 44 a thus deforms elastically and the rear end of the first return spring 44 a comes close to the second support member 43 b.

In this compressor, as the inclination angle of the swash plate 5 becomes smaller and the stroke of the pistons 9 decreases, the top dead center position of the first heads 9 a moves away from the first valve forming plate 39. Thus, in the compressor, when the inclination angle of the swash plate 5 approaches 0 degrees, compression work is performed slightly in the second compression chamber 230, whereas compression work is not performed in the first compression chamber 210.

When the control valve 15 c shown in FIG. 2 reduces the opening degree of the low-pressure passage 15 a, the pressure in the pressure regulation chamber 31 increases due to the pressure of the refrigerant gas in the first discharge chamber 29 a, and thereby the pressure in the control pressure chamber 13 c increases. Thus, the movable body 13 a of the actuator 13 moves rearward in the swash plate chamber 33 as shown in FIG. 1 against the piston compression force acting on the swash plate 5.

Consequently, in the compressor, the movable body 13 a pulls the opposite end side of the swash plate 5 rearward in the swash plate chamber 33 about the action axis M3 via the first and second pulling points 132 a and 133 a of the first and second arms 132 and 133. Thus, in the compressor, the opposite end side of the swash plate 5 pivots counterclockwise around the action axis M3. Also, the rear side of the lug arm 49 pivots clockwise around the first pivot axis M1 and the front end of the lug arm 49 pivots clockwise around the second pivot axis M2. The lug arm 49 thus moves away from the flange 433 of the second support member 43 b. In this way, the swash plate 5 pivots in a direction opposite to the direction in the above-described case of decreasing the inclination angle, using the action axis M3 as a point of action and using the first pivot axis M1 as a fulcrum. This increases the inclination angle of the swash plate 5 with respect to the direction perpendicular to the drive axis O of the drive shaft 3 and thus increases the stroke of the pistons 9. Consequently, the discharge capacity of the compressor per rotation of the drive shaft 3 increases. The inclination angle of the swash plate 5 shown in FIG. 1 is the maximum value in this compressor. When the inclination angle of the swash plate 5 has reached the maximum value, the rear wall 130 of the movable body 13 a abuts the first flange 430.

In this way, in the compressor, to increase the inclination angle of the swash plate 5, the movable body 13 a pulls the swash plate 5 via the first and second pulling points 132 a and 133 a of the first and second arms 132 and 133. In other words, in this compressor, when the swash plate 5 is displaced in the direction of increasing the inclination angle, the movable body 13 a moves away from the swash plate 5. Consequently, in the compressor, even if the rear wall 130 and the circumferential wall 131 are upsized in order to reliably increase the discharge capacity using the pressure rise in the control pressure chamber 13 c, no interference will occur between the circumferential wall 131 and the swash plate 5. Therefore, it is possible in this compressor to prevent upsizing of the swash plate chamber 33 when the rear wall 130 and the circumferential wall 131 of the movable body 13 a are upsized.

Furthermore, in this compressor, the coupling mechanism 14 includes the first and second arms 132 and 133. The first arm 132 is provided with the first pulling point 132 a for applying a pulling force to the swash plate 5 and the second arm 133 is provided with the second pulling point 133 a for applying a pulling force to the swash plate 5. In the case where the inclination angle is increased by pulling the swash plate 5, less compressive reaction force and less suction reaction force are exerted as compared with the case where the inclination angle is increased by the pushing swash plate 5. Therefore, in this compressor, a large pulling force is not required to increase the inclination angle of the swash plate 5.

Furthermore, in this compressor, the first arm 132 and the second arm 133 are arranged across the imaginary plane X defined by the drive axis O, top dead center position of the swash plate 5, and the bottom dead center position of the swash plate 5. The first pulling point 132 a and the second pulling point 133 a are set on the first arm 132 and the second arm 133, respectively. The first arm 132 and the second arm 133 are able to apply the pulling force at two points, i.e., the first pulling point 132 a and the second pulling point 133 a. Consequently, in this compressor, the pulling force that each of the first arm 132 and the second arm 133 exerts on the swash plate 5 can be made less as compared with the case where, for example, the coupling mechanism 14 has only a single arm. In this compressor, although the movable body 13 a pushes the swash plate 5 via the first and second arms 132 and 133 when the inclination angle of the swash plate 5 is decreased, the pushing force at that time is not so large. This is because a centrifugal force acts on a rotation body including the swash plate 5 and the movable body 13 a in the direction of decreasing the inclination angle.

For these reasons, as described above, even when the size of the rear wall 130 and the circumferential wall 131 is increased in this compressor, the rigidity of the first and second arms 132 and 133 required thereby can be made lower. Therefore, it is possible in this compressor to prevent upsizing of the first and second arms 132 and 133, i.e., upsizing of the coupling mechanism 14.

Furthermore, in this compressor, the first imaginary region S1 and the second imaginary region S2 are set in the swash plate chamber 33. When the movable body 13 a is attached to the drive shaft body 30, the first arm 132 is positioned in the first imaginary region S1 and the second arm 133 is positioned in the second imaginary region S2. Consequently, in the compressor, the first arm 132 and the second arm 133 do not obstruct the pistons 9 reciprocating in the first to fifth rear-side cylinder bores 21 a to 21 e and the first to fifth front-side cylinder bores 23 a. Therefore, it is possible to dispose the first arm 132 and the second arm 133 in the vicinity of the first to fifth rear-side cylinder bores 21 a to 21 e and the first to fifth front-side cylinder bores 23 a, i.e., in the vicinity of the respective pistons 9.

Therefore, the compressor according to the embodiment, in which the discharge capacity is changed by the actuator 13, exhibits high controllability while realizing reduction in size.

In particular, the swash plate 5 of this compressor is provided with the pulled portion 45 c that protrudes between the first arm 132 and the second arm 133. The pulled portion 45 c is fitted to the recessed portion 134 of the movable body 13 a, and in this state, the first and second arms 132 and 133 are connected with the swash plate 5. Thereby, in the compressor, when the movable body 13 a rotates together with the drive shaft 3, a driving force is transmitted between the first and second arms 132 and 133 and the pulled portion 45 c. Therefore, in the compressor, the movable body 13 a rotates stably together with the drive shaft 3 and the swash plate 5 also rotates stably together with the movable body 13 a and thus together with the drive shaft 3.

In addition, the third pin 47 c extending in a direction perpendicular to the drive axis O is inserted through the first arm 132, the pulled portion 45 c, and the second arm 133. Consequently, the first arm 132, the pulled portion 45 c, and the second arm 133 can be coupled together easily. It is also possible to reduce the number of components and facilitate manufacturing as compared with the case of, for example, using different pins to couple the first arm 132 and the pulled portion 45 c and couple the second arm 133 and the pulled portion 45 c. Furthermore, in this compressor, the third pin 47 c is less likely to come off the first and second arms 132 and 133 and the pulled portion 45 c, and thus reliability is improved.

Although the present invention has been described above by referring to the embodiment, needless to say, the present invention is not limited to the above embodiment and may be modified and applied as required without departing from the gist of the present invention.

For example, the compressor may be configured as a variable displacement single head swash plate type compressor by forming cylinder bores only in either of the first cylinder block 21 and the second cylinder block 23.

Also, the control mechanism 15 may be configured such that the control valve 15 c is provided on the high-pressure passage 15 b while the orifice 15 d is provided in the low-pressure passage 15 a. In this case, it is possible to adjust the opening degree of the high-pressure passage 15 b using the control valve 15 c. Thereby, the pressure in the control pressure chamber 13 c can be increased quickly due to the pressure of refrigerant gas in the first discharge chamber 29 a, and the discharge capacity can be increased quickly.

INDUSTRIAL APPLICABILITY

The present invention is applicable to air-conditioning apparatus and the like.

REFERENCE SIGNS LIST

1 Housing

3 Drive shaft

5 Swash plate

7 Link mechanism

9 Piston

11 a, 11 b Shoe (conversion mechanism)

13 Actuator

13 a Movable body

13 b Partition body

13 c Control pressure chamber

14 Coupling mechanism

15 Control mechanism

21 a First rear-side cylinder bore (first cylinder bore)

21 b Second rear-side cylinder bore (second cylinder bore)

21 c Third rear-side cylinder bore (third cylinder bore)

27 a First suction chamber

27 b Second suction chamber

29 a First discharge chamber

29 b Second discharge chamber

33 Swash plate chamber

45 c Pulled portion

47 a First pin (connecting portion)

47 c Third pin (pin)

132 First arm

133 Second arm

210 First compression chamber

230 Second compression chamber

L1 First tangential line

L2 Second tangential line

L3 Third tangential line

L4 Fourth tangential line

O Drive axis

S1 First imaginary region

S2 Second imaginary region 

1. A variable displacement swash plate type compressor comprising: a housing in which a suction chamber, a discharge chamber, a swash plate chamber, and at least one cylinder bore are formed; a drive shaft extending along a drive axis and rotatably supported in the housing; a swash plate rotatable in the swash plate chamber along with rotation of the drive shaft; a link mechanism that is provided between the drive shaft and the swash plate and permits change of an inclination angle of the swash plate in a direction perpendicular to the drive axis of the drive shaft; a piston reciprocally accommodated in the cylinder bore; a conversion mechanism that reciprocates the piston in the cylinder bore along with rotation of the swash plate at a stroke corresponding to the inclination angle; an actuator that is disposed in the swash plate chamber and capable of changing the inclination angle; and a control mechanism that controls the actuator, wherein the suction chamber and the swash plate chamber communicate with each other, the actuator includes a partition body provided on the drive shaft, a movable body that is coupled to the swash plate via a coupling mechanism and movable with respect to the partition body along the drive axis of the drive shaft, and a control pressure chamber that is defined by the partition body and the movable body and moves the movable body by introducing a refrigerant from the discharge chamber, the movable body is disposed so as to increase the inclination angle by pulling the swash plate when pressure in the control pressure chamber increases, the link mechanism includes a coupling portion that is coupled to the swash plate, and the coupling mechanism is disposed on an opposite side of the coupling portion with respect to the drive shaft and includes a first arm and a second arm provided at the movable body across the drive axis.
 2. The variable displacement swash plate type compressor according to claim 1, wherein the at least one cylinder bore comprises at least a first cylinder bore, a second cylinder bore, and a third cylinder bore, the first cylinder bore, the second cylinder bore, and the third cylinder bore are arranged concentrically at equal angular intervals around the drive axis in the housing, a first imaginary region and a second imaginary region are set in the swash plate chamber, the first imaginary region being defined by a first tangential line drawn from the drive axis to the first cylinder bore at a side of the second cylinder bore and a second tangential line drawn from the drive axis to the second cylinder bore at a side of the first cylinder bore, the second imaginary region being defined by a third tangential line drawn from the drive axis to the second cylinder bore at a side of the third cylinder bore and a fourth tangential line drawn from the drive axis to the third cylinder bore at a side of the second cylinder bore, and the first arm is located within the first imaginary region and the second arm is located within the second imaginary region.
 3. The variable displacement swash plate type compressor according to claim 1, wherein the swash plate is provided with a pulled portion that protrudes between the first arm and the second arm, and a driving force is transmitted between the first arm, the second arm, and the pulled portion.
 4. The variable displacement swash plate type compressor according to claim 3, wherein a pin extending in a direction perpendicular to the drive axis is inserted through the first arm, the pulled portion, and the second arm. 